The calculated distance (air line) between Kathu and Nakhon Si Thammarat is approximately 117 miles respectively 189 kilometers.
By car or train, the actual journey to Nakhon Si Thammarat is certainly longer, as only the direct route (as the crow flies) between Kathu and Nakhon Si Thammarat has been calculated here.
Air line (approximately)
189 kilometers
102 nautical miles